Justices Act 1886

When complaint is made before a justice of a simple offence, the justice may, upon oath being made before the justice substantiating the matter of the complaint to the justice’s satisfaction, instead of issuing a summons, issue in the first instance the justice’s warrant to apprehend the defendant, and to cause the defendant to be brought before justices to answer the complaint and to be further dealt with according to law.

The justice may issue a warrant under subsection (1) for a simple offence, not being an indictable offence, only if the justice is satisfied—

proceeding by way of complaint and summons for the offence would be ineffective; or

the Act or law creating the offence authorises the issue of a warrant in the first instance.